Method and apparatus for reducing a program size while maintaining branching time properties and automated checking of such reduced programs

Abstract

A method and apparatus are provided a method and apparatus for reducing a program that preserves branching time properties, including existential and universal aspects. An alternating transition system (ATS) is abstracted, formed by a product of a program, M, with an alternating tree automaton, A, for a property, f. The disclosed program abstraction method generates the abstract program and an altered version of the branching time property, f. An automated program check, such as a model check, is performed on the abstract program for the altered branching time property. The invention provides semantic completeness: i.e., whenever a program satisfies a property, this can be shown using a finite-state abstract ATS produced by the method. Choice predicates can be employed to help resolve nondeterminism at OR states, and rank functions can be employed to help preserve progress properties.

Description

FIELD OF THE INVENTION The present invention relates generally to automated program checking techniques, and more particularly, to methods and apparatus for reducing the size of programs prior to such automated program checking techniques. BACKGROUND OF THE INVENTION Software programs can often be difficult to test or verify. In order to efficiently and effectively evaluate software programs, it is often necessary to reduce the size of the program, for example, using abstraction techniques. Most current abstraction methods preserve universal temporal properties, such as those expressible in linear temporal logic (LTL) and Universal Computation Tree Logic (ACTL). In several settings, there is a need for methods that preserve branching time properties, including mixed existential and universal branching time properties. For example, branching time properties must be maintained to analyze programs with unresolved non-determinism, or to analyze process-environment interaction. See, fo...

AI Technical Summary

Benefits of technology

Generally, a method and apparatus are provided a method and apparatus for reducing a program that preserves branching time properties. In particular, the invention simultaneously preserves the existential and universal aspects of a branching time property, and does not rely on bisimulation. The disclosed program abstraction method abstracts an alternating transition system (ATS) formed by a product M×A of a program, M, with an alternating tree automaton, A, for a property. An abstract domain contains a set of abstr...

Problems solved by technology

Software programs can often be difficult to test or verify.

Unfortunately, to preserve all branching time properties in a similar manner requires a bisimulation between the two programs (which is too restrictive).

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